Investigators were given a six-figure budget over the next 30 days to examine the league's finances, allegations of previous discriminatory conduct and compensation to past Commissioner David Stern and current Commissioner Adam Silver, said the person who spoke to The Associated Press on Thursday night on condition of anonymity. The person wasn't authorized to talk publicly.

The person said the investigators also are looking into whether other owners made any off-color jokes, or racist or sexist remarks.

"The gloves are off, as they say," the person said. "Have them dig up all the dirt they can find."

After initially consenting to the sale of the Los Angeles Clippers, Sterling has done a total 180 and gone on the attack. In a statement released Tuesday, he called the NBA a "band of hypocrites and bullies." It appears this is how he intends to back up that claim.

The person who spoke to the AP said Donald Sterling reluctantly agreed to hire private investigators after this week's legal proceedings in probate court. The NBA submitted a legal filing Wednesday urging a judge to confirm Shelly Sterling's authority to sell the team.

"He realized these guys will literally go to any low to get this sold," the person said. "Even if it gets (him) nothing other than exposing all these guys and shaking up the league and seeing a change in the leadership of the league, it'll be worth it to him."

The firms will be engaged in an "audition" of sorts, the individual said: "Whoever delivers the best (material) is going to stay on for the next round and it might be all four of them...29 owners is not a small undertaking."

The sale of the Clippers to Steve Ballmer is in limbo, as Sterling and his wife will take their dispute over control of the Sterling Family Trust to probate court in July. If it is ruled that Sterling is, in fact, "mentally incapacitated" and Shelly had the right to become the sole trustee, the NBA will proceed with its board of governors vote on the sale on July 15. A leaked court document filed by Shelly's lawyers shows that Sterling was unable to spell "world" backwards and couldn't correctly number a clock.

Donald Sterling is fighting back against the league that banned him for life. (USATSI)